Fucoidan a sulfated polysaccharide from brown algae is a potent modulator of connective tissue proteolysis

Fucoidans are sulfated fucosylated polymers from brown algae cell wall that exhibit some heparin/heparan sulfate properties. We previously demonstrated that these polysaccharides were able in vitro to stimulate dermal fibroblast proliferation and extracellular matrix deposition. Here, we investigated the action of a 16kDa fucoidan fraction on parameters involved in connective tissue breakdown. This fucoidan is able to inhibit gelatinase A secretion and stromelysin 1 induction by interleukin-1beta on dermal fibroblasts in culture. Furthermore, we observed that fucoidan increases the rate of association of MMPs with their specific inhibitors namely TIMPs. Using tissue sections of human skin in ex vivo experiments, we evidenced that this polysaccharide was able to minimize human leukocyte elastase activity resulting in the protection of human skin elastic fiber network against the enzymatic proteolysis due to this serine proteinase. These results suggested that fucoidan could be used for treating some inflammatory pathologies in which uncontrolled extracellular matrix degradation takes place.     

Co-occurrence of the multicopper oxidases tyrosinase and laccase in lichens in sub-order peltigerineae

BACKGROUND AND AIMS: Following previous findings of high extracellular redox activity in lichens and the presence of laccases in lichen cell walls, the work presented here additionally demonstrates the presence of tyrosinases. Tests were made for the presence of tyrosinases in 40 species of lichens, and from selected species their cellular location and molecular weights were determined. The effects of stress and inhibitors on enzyme activity were also studied. METHODS: Tyrosinase and laccase activities were assayed spectrophotometrically using a variety of substrates. The molecular mass of the enzymes was estimated using polyacrylamide gel electrophoresis. KEY RESULTS: Extracellular tyrosinase and laccase activity was measured in 40 species of lichens from different taxonomic groupings and contrasting habitats. Out of 20 species tested from the sub-order Peltigerineae, all displayed significant tyrosinase and laccase activity, while activity was low or absent in other species tested. Representatives from both groups of lichens displayed low peroxidase activities. Identification of the enzymes as tyrosinases was confirmed by the ability of lichen thalli or leachates derived by shaking lichens in distilled water to metabolize substrates such as L-dihydroxyphenylalanine (DOPA), tyrosine and epinephrine readily in the absence of hydrogen peroxide, the sensitivity of the enzymes to the inhibitors cyanide, azide and hexylresorcinol, activation by SDS and having typical tyrosinase molecular masses of approx. 60 kDa. Comparing different species within the Peltigerineae showed that the activities of tyrosinases and laccase were correlated to each other. Desiccation and wounding stimulated laccase activity, while only wounding stimulated tyrosinase activity. CONCLUSIONS: Cell walls of lichens in sub-order Peltigerineae have much higher activities and a greater diversity of cell wall redox enzymes compared with other lichens. Possible roles of tyrosinases include melanization, removal of toxic phenols or quinones, and production of herbivore deterrents.     

An automatic diagnostic system of coronary artery lesions in Kawasaki disease using intravascular optical coherence tomography imaging

Intravascular optical coherence tomography (IV‐OCT) is a light‐based imaging modality with high resolution, which employs near‐infrared light to provide tomographic intracoronary images. Morbidity caused by coronary heart disease is a substantial cause of acute coronary syndrome and sudden cardiac death. The most common intracoronay complications caused by coronary artery disease are intimal hyperplasia, calcification, fibrosis, neovascularization and macrophage accumulation, which require efficient prevention strategies. OCT can provide discriminative information of the intracoronary tissues, which can be used to train a robust fully automatic tissue characterization model based on deep learning. In this study, we aimed to design a diagnostic model of coronary artery lesions. Particularly, we trained a random forest using convolutional neural network features to distinguish between normal and diseased arterial wall structure. Then, based on the arterial wall structure, fully convolutional network is designed to extract the tissue layers in normal cases, and pathological tissues regardless of lesion type in pathological cases. Then, the type of the lesions can be characterized with high precision using our previous model. The results demonstrate the robustness of the model with the approximate overall accuracy up to 90%.      

Postnatal changes in testicular development and androgen receptors immunolocalization in D'Man ram lambs

The purpose of this study was to characterize testicular development in D'Man ram lambs, focusing primarily on androgen receptors (ARs) immunolocalization in the adenohypophysis and testis that is not still known in the D'Man ram lamb. Lambs (n = 12) were divided into four groups (three lambs per group). Adenohypophysis and testis were fixed and paraffin embedded; cross-section (3 μm) were stained and evaluated with immunohistochemistry. Testis weight increased at a greater rate between two and five months after birth, which was associated with remarkable changes in testicular histology, including significant increases in the diameter of seminiferous tubules. Spermatogenesis started between three and five months after birth; lumen and elongated spermatids were observed for the first time in three and four months-old animals respectively. ARs detected with immunohistochemistry were located in the nuclei and cytoplasm of adenohypophysis cells, and only in nuclei of testis cells (Leydig, Sertoli, peritubular myoid and germ cells).     

Molecular Nature of Spontaneous Mutations in Mouse Lactate Dehydrogenase-a Processed Pseudogenes

The presence of at least ten mouse LDH-A pseudogenes was demonstrated in the genomic blot analysis, and four different processed pseudogenes have thus far been isolated and characterized. In this report, the nucleotide sequences to two different mouse lactate dehydrogenase-A processed pseudogenes, M11 and M14, were determined and compared with the protein-coding sequences of the mouse and rat LDH-A functional genes. In the pseudogene M11, the sequence of 64 nucleotides from codon no. 257 to 278 was tandemly duplicated. In the pseudogene M14, the sequence of 22 nucleotides from codon no. 68 to 75 was replaced by an inserted repetitive sequence of 242 nucleotides homologous to a mouse truncated R element. The pattern of nucleotide substitutions accumulated in mouse LDH-A pseudogenes M11 and M14, as well as that of pseudogene M10 identified previously, was analyzed, and the substitution frequencies of the C or G at the CG dinucleotide were found to be high.     

In CK2 inactivated cells the cyclin dependent kinase inhibitor Sic1 is involved in cell-cycle arrest before the onset of S phase

Protein kinase CK2 is a heterotetramer composed of two catalytic and two regulatory subunits. In Saccharomyces cerevisiae the catalytic subunits (alpha and alpha') are encoded by the CKA1, CKA2 genes. cka1Deltacka2(ts) mutants arrest cell cycle in both G1 and G2/M at 37 degrees C. Hence, it has been proposed that CK2 plays an important role in cell-cycle progression and several cell-cycle proteins have been reported to be CK2 substrates. We have previously shown that Sic1, the inhibitor of Clb5-Cdc28 complexes required for the G1/S transition, is a physiologically relevant CK2 substrate. Here we show that CK2 inactivation up-regulates Sic1 level resulting in severe down-regulation of Clb5-Cdc28 kinase activity. Concurrent inactivation of Sic1 and CK2 leads to accumulation of cells with a post-synthetic DNA content and short/elongated spindles, typical of cells arrested in mitosis. These findings indicate that Sic1 plays a major role during G1 arrest of CK2-inactivated cells.     

Histological and immunohistological aspects of the ovarian cycle of the algerian wild sand rat, Psammomys obesus Cretzschmar, 1828

The sand rat, Psammomys obesus, is largely used as a model for studying several metabolic disorders. In order to perform breeding laboratory conditions, the reproductive function of this species was investigated. Using histological and immunohistochemical techniques, several aspects of the ovaries were studied throughout the sexual cycle. During the ovarian cycle, the different stages of folliculogenesis, from primordial to Graafian follicle, have been shown; the differentiation of both granulosa and theca cells, the formation of the antrum, cumulus oophorus and corona radiate were described. Broken follicles and corpora lutea have been observed, confirming a spontaneous ovulation in isolated females. Steroid activities were analysed using immunohistochemical techniques. Estrogen, androgen and progesterone hormones were visualized in the different compartments of the ovary.     

Connexin 43 confers resistance to hydrogen peroxide-mediated apoptosis

The current study aimed to understand the anti-apoptotic effect of overexpressed gap junction forming protein connexin (Cx) 43 in C6 glioma cells. C6 cells exposed to hydrogen peroxide (H2O2) or staurosporine demonstrated morphological and biochemical changes consistent with apoptosis, whereas C6 cells expressing Cx43 demonstrated relative resistance to H2O2, but not to staurosporine. This selective protection against H2O2 was due to inhibition of caspase-3 activation in Cx43 expressing cells. siRNA knockdown experiments in rat primary astrocytes confirmed the presence of endogenous Cx43-mediated anti-apoptotic effect. Cx43 interacts with the upstream apoptosis signal-regulating kinase 1 known to mediate H2O2-induced apoptosis providing a possible mechanism for protection. These findings provided new evidence for regulation of the mitogen activated protein kinase pathway and apoptosis by Cx43 implicating this protein in intracellular signaling beyond its role as a gap junction forming protein on the plasma membrane.     

Studies on stomatal function, epicuticular wax and stem-root transition region of polyethylene glycol-treated and nontreatedin vitro grape plantlets

Summary Scanning electron microscopy, light microscopy, and gravimetric analysis was used to evaluate stomatal function, epicuticular wax, and the stem-root transition region of grape (Vitis sp. ‘Valiant’) plantlets grownin vitro, polyethylene glycoltreatedin vitro, and greenhouse-grown plants. Scanning electron microscopic studies of leaf surfaces ofin vitro-grown plants showed widely open stomata as compared to leaf stomata of polyethylene glycol-treatedin vitro-cultured and greenhouse-grown plants. Ultrastructurally, leaf epicuticular wax ofin vitro plants was less dense than in their polyethylene-treated and greenhouse counterparts. Quantitatively,in vitro-grown plants had reduced epicuticular was as compared to polyethylene glycol-treated and greenhouse-grown plants. Light microscopic studies showed no obvious differences in the vascular connections in the stem-root transition region ofin vitro-cultured, polyethylene glycol-treatedin vitro-cultured, and greenhouse-grown plants. It is therefore likely that the rapid wilting and desiccation observed after transplantingin vitro grape plantlets is due to their defective stomatal function and reduced epicuticular wax and may not be due to poor water transport associated with vascular connection.